Spatial Surgical is developing a novel, first-in-class orthopedic laser system that rapidly and safely ablates soft tissue and bone through a single handpiece. Spatial?s technology couples a laser with a real-time digital video system to offer computer-guided surgery that stands to replace traditional orthopedic saws, drills, and cauterization tools. Spatial?s laser cuts soft and hard tissue via molecular absorption while saws, drills and scalpels compress, shear and tear the tissue. The laser?s molecular absorption is referred to as ?cold coupling?, as no heat is transferred to the surrounding tissue, which eliminates the necrosis, smear layer and cauterization common with mechanical tools. The elimination of dead tissue, which the body must absorb, leads to less pain, faster healing and less post-operative complications (infections, implant loosening, etc.). In-vivo orthopedic surgery research has defined the steps to commercialization for an orthopedic laser surgical system. While successfully cutting bone necrosis-free with rapid healing, limitations noted in the research were slow ablation speed, tapered cutting and lack of depth control. Additionally, there are practical medical device engineering developmental needs. For example, the CO2 ablation laser is invisible so a visible aiming beam needs to be added colinear to the CO2 laser beam, so surgeons can view where the laser will ablate the tissue. This SBIR project has three objectives, model a green aiming beam?s optical requirements, model spinning wedges to rotate the CO2 ablation laser and define cutting speed by ablating porcine femur bone samples. To define the final laser system?s optical scheme, an OSLO software model for the CO2 ablation laser coupled with a green aiming beam is developed. The Fraunhofer Institute researched eliminating tapered laser cutting and found that laser beam rotational symmetry is integral to eliminating taper. An optical model is developed to add spinning optical wedges into the CO2 beam path to rotate and homogenize the CO2 laser mode. Finally, a bench top prototype with a CO2 laser and CNC controlled mirrors is built to define the fluence and repetition rate required to cut bone at clinically acceptable speeds. Single pass patterns will be cut in flat porcine femur bone samples to investigate the effect of fluence, pattern spacing and repetition rate on the volumetric cutting speed. The volume removed will be measured with a confocal microscope to define the volumetric removal rate, VRR. From the VRR data an algorithm will be generated to define repetition rates, fluence levels and power levels that demonstrate necrosis-free bone ablation at clinically viable speeds.